Conventionally, an image forming apparatus is equipped with a paper feeding device. The paper feeding device conveys a paper stored in a cassette to an image forming section. The cassette is arranged to be multiple according to the paper size and the like. In a recent image forming apparatus, a request that an image is formed on a paper (thick paper) of which the thickness is thick is increasing.
Incidentally, a conveyance path of the paper is not a straight line and a conveyance direction of which may be changed. Therefore, a conveyance speed of the paper is slow at a conversion point of the conveyance direction, which results in a stall of the paper. Specially, the thicker the thickness of the paper is, the higher the possibility of the stall is. Thus, it is necessary to increase a conveyance force of the thick paper. Further, in order to prevent the stall of the paper when the thick paper is conveyed, a plurality of plans such as devising the shape of the conveyance path, reducing the conveyance resistance and the like is proposed.
In order to suppress that the conveyance speed of the paper is slow at the conversion point of the conveyance direction of the paper, it is exemplified to use a conveyance roller and a conveyance belt in the conveyance path. The conveyance belt has a structure hanging on two pulleys. In a case of feeding the paper using the conveyance roller and the conveyance belt, the paper picked up from the cassette is received by the conveyance belt. Then, the direction of the paper is changed towards a nip part between the conveyance roller and the conveyance belt due to the friction force of the belt.
However, if the paper enters at an angle more than 45 degrees with respect to the conveyance belt, the paper is stalled. The worst case is that the paper cannot be conveyed. Further, damages may be applied to the paper. Specifically, when conveying the thick paper, the thick paper cannot be conveyed and a degree of applying the damages to the thick paper is strong.